<a href=”http://rockrivertimes.com/wpapp/wp-content/uploads/Vortex.jpg”><img alt=”The polar vortex, also known as a polar cyclone, is an area of upper-level low pressure that typically develops in each hemisphere during winter months, causing extremely cold temperatures.” src=”http://rockrivertimes.com/wpapp/wp-content/uploads/Vortex-500×358.jpg” width=”400″ height=”286″ /></a> The polar vortex, also known as a polar cyclone, is an area of upper-level low pressure that typically develops in each hemisphere during winter months, causing extremely cold temperatures.

<strong>By Jim Hagerty</strong>
Staff Writer

This week’s extreme cold spell can be attributed to the polar vortex, making Rockford one of the coldest cities in the country between Jan. 6 and Jan. 7.

Within the last few days, the polar vortex has made an abrupt and unusual shift south, blanketing areas with pockets of dangerously cold air.

The movement is considered unusual because the polar vortex usually swirls over the polar regions during winter months, weather experts say.

Since the first of the year, the Rockford area has seen a blistering mixture of ice and snow because of the vortex. Between Dec. 30 and Jan. 4, the stateline saw several inches of accumulation, followed by sub-zero temperatures and wind chills well past minus 40 degrees by Monday, Jan. 6.

The temperature in Rockford reached a bone-rattling minus 18 Monday with a wind chill factor of 45 below zero.

Early Tuesday, as Rockford hovered around minus 10, lows in other cities broke decades-old records, but didn’t match local marks. However, suddenly cold air came as a shock as the vortex meandered south.

“Philly and Atlanta recorded their first January record lows in the 21st century on Tuesday morning,” AccuWeather Senior Meteorologist Alex Sosnowski said.

Atlanta fell to 6 degrees Tuesday morning while it was 4 in Philadelphia with sub-zero wind chill factors for most of the day.

The Zanesville, Ohio temperature of minus 8 broke the 3-below-zero record for the date set in 1968. The Muskingum County seat was also socked with wind chills of around minus 30.

Record temperatures were also recorded in Atlanta (6 degrees, wind chill of minus 11), Baltimore (3 degrees, wind chill of minus 20) and New York (4 degrees, wind chill of minus 20).